Machine for straightening and polishing rods and tubes



June 27, 1939. c D|DDEN 2,163,669

MACHINE FOR STRAIGHTENING AND POLISHING RODS AND TUBES Filed March 31. 1958 2 Sheets-Sheet l f'fze June 27, 1939. D|DDEN 2,163,669

MACHINE FOR STRAIGHTENING AND POLISHING RODS AND TUBES Filed March 31, 1938 2 Sheets-Sheet 2 /6 fi 4 I /7 .3 m I 5 9 Z 55 I I [1 i I L 36 5/ f 5 6w fi i n "I 9 I 7 Z0 II "a5; 0 \Q 35 F 3/36 25 3% k o O J: a 3 i 4% /9 mm V iiii! Patented June 27, 1939 UNITED STATES I MACHINE FOB, STRAIGHTENING AND POL- ISHING RODS AND TUBES Carl Didden, St. Louis, Mo. Application March 31, 1938, Serial No. 199,194

One of the principal objects of the present invention is to devise a machine which will both straighten and polish rods and tubes in one and the same passage therethrough. Other objects are to provide for the quick and accurate adjust,-

ment of the machine for work pieces of diflerent diameters, to facilitate the making of adjustments, and to devise a machine of simple construction and of relatively small cost. The invention consists principallyin two concave hyperboloidal rolls larger at one end than at the other arranged with their axes parallel and their small ends overlapping, in connection with a third hyperboloidal roll whose axis crosses the axes of the other two rolls and is in a plane parallel with the axes of said first-mentioned rolls. Italso consists in mounting the parallel rolls on a single yoke or carrier which is movable to shift the axes of said rollers in their plane. It also con- :20 sists in means for adjusting the obliquity of the third roll in a plane parallel with the plane of the axes of the first-mentioned rolls, together with means for adjusting the plane of the axis of the third roll relative to the plane of the axes of 25 the first two mentioned rolls. It also consists in the arrangements and combinations of parts hereinafter described and claimed.

In the accompanying drawings which form part of this specification and wherein like reference numerals 'refer to like parts whereverthey occur,

Fig. 1 is a plan view of a machine embodying my invention;

Fig. 2 is an end elevation'thereof;

Fig. 3 is a side elevation thereof;

' 35 Fig. 4 is a fragmentary horizontal section on the line 4-4 in Fig. 2;

Figs. 5 and 6 are fragmentary vertical sections on the line'S-S and 6--6 in Figs. 1 and 2, respectively; and Figs. 7, 8 and 9 are a plan, side elevation and end view, respectively, showing the twin and pressure rolls operating on the work.

The framework of my machine comprises a base I, pillars or'columns Z-supported thereby and a heavy top plate '3 mounted on said pillars. On the base I is a heavy plate member 4 with upstanding lugs 5 that are perforated to receive the bearings of the necks 5a of two rolls 8 which are,

50 for convenience, hereinafter: called -twin rolls". These twin rolls are arranged with their axes parallel wltheach other, preferably in a horizontal plane, and the four lugs which support their roll necksare arranged accordingly. This heavy 55 plate member 4 is pivotally mounted on the base i, as by means of a pivot member 4a in the base piece (see Fig. 2).

The twin rolls 6 havehyperboloidal surfaces concavedendwise but are oflarger diameter at one end than at the other. These twin rolls are 5 disposed with their small ends in overlapping relation. The major portion of the hyperboloidal surface of each of the twin rolls is so shaped that the contact thereof with .a straight work piece will approximate a straight line contact when the 10 rolls are set at their maximum angle to the work piece. When such twin rolls are set at an ordinary working angle to the work piece and the work piece is flexed by the pressure roll hereinafter mentioned, the work piece will make a short approximately straight contact with each of the twin rolls near the large end of the roll.

The ends of the twin rolls are tapered ofl to a surface approaching a spherical surface so that as the end of the bar or tube or work piece enters the rolls, the rounded small end of 'the twin roll will have the action of guiding the bar into proper relationship with the pressure roll. When the machine is to be used for passing the work piece in one direction only, then only one of the rolls will have a rounded small end. It is desirable in some cases to operate the machine in either direction and thereforethe small end of each of the twin rolls should be rounded. The large end should have rounded edges such as are generally considered good shop practice in order to prevent the marking of the work piece in case there is any whipping action as it enters the machine. 1

In a plane parallel to and preferably above the twin rolls 6 is a third roll 'I, which is hereinafter calledthe pressure. roll. This pressure roll has a concave hyperboloidal surface which is symmetrical about its plane of least diameter.

It likewise is so shaped that the work piece will 40 have a substantially. straight line contact therewith when the roll is placed at the maximum working angle with the work piece. The ends of said pressure roll are rounded like those of the twin rolls. This third roll I has its roll necks supported in the downturned forks of a yoke 8 which is pivotally supported, as at 8a, by a crosshead lb .or platen whose corners are perforated vertically to fit over the four pillars of the frame sov as to be capable of'sliding vertically thereon. This cross-head has bosses 9 on its upper surface with threaded holes thereinin which are heavy vertical screws 10 mounted on the top plate 3 of. the frame. toturn without moving 'endwise. The upper ends of the screws, which work in I the top of the cross-head, are provided with gears H which mesh with a pinion E2 on a shaft l3 mounted in the top plate of the frame. The upper end of this shaft is provided with a bevel gear l4 driven by a bevel pinion l5 on a shaft 16 which is provided with a large wheel I! adapted to be turned by hand. Thus by turning the hand wheel, the yoke may be adjusted vertically to suit work pieces of difieren't diameters. The height of the twin lower rolls is preferably fixed, as there is no need to vary it.

The pressure roll 1 is disposed parallel with the plane of the axes of the twin or lower rolls 6 and preferably with its axis horizontal, and the vertical plane through the axis of the upper roll intersects the plane of the axes of the twin rolls in a line which is oblique to the twin roll axes. The pass line or axis of the work piece in its passage through the machine is about midway between the planes of the pressure and twin roll axes. The vertical plane of the pass line intersects the vertical plane of the pressure roll axis in a verticalline midway between the axes of the twin rolls, which line is hereinafter called the vertical axis of the machine. The pressure roll axis is inclined to the vertical plane of the pass line to substantially the same extent but in the opposite direction to the inclination of the axes of the twin rolls. The angle of inclination of all of the roll axes to the vertical plane of the pass line varies with the setting of the rolls but is usually betweentwenty and forty degrees.

As stated, the yoke 8, which supports the pressure roll I, is capable of limited rotation on a vertical axis 8a, which, as shown in Fig. 3, substantially coincides with the vertical axis of the machine. To efiect such rotation, a link I8 has one end pivotally secured to a lug l9 on the yoke and its other end passes loosely through an opening provided therefor in the end of the crosshead 81), and its free end is provided with a screw thread upon which works a threaded hand nut 20. By this arrangement, when the nut 20 is set with its end against the face of the end of the cross-head, further turning of the nut causes the link to pull and turn the yoke in one direction. A second device of the same kind is used to turn the yoke in the opposite direction. By these means, the yoke and the upper roll can be ac-.

curately set in correct angular adjustment about their vertical axis of adjustment, namely, about the vertical axis of the machine. The mechanism for swinging the twin roll supporting plate 4 about its pivotal axis 4a (which also coincides with the vertical axis of the machine as shown in Figs. 1 and 2) preferably comprises a rod lb threaded through a bracket 4c clamped to one of the pillars 2 and having a rotary but non-axial sliding connection at one end with a block 411 that is secured to said supporting plate. The other end of the rod 4b is provided with a suitable hand wheel 4e; and the plate 4 is locked in the desired position of its rotary adjustment by capscrews 4 that extend through arcuate slots 49 in said plate and are threaded into the base I.

The twin rolls are driven by shafts 2| that are provided with beveled gears 22 which mesh with beveled pinions 23 on a propeller shaft 24 connected by universal joints 25 with a shaft 26 of a change speed mechanism 21 connected to a suitable prime mover 28 as, for instance, connected to an electric motor by a belt drive 29. The upper roll is suitably driven from. the same source of power. In the particular machine illustrated, the shaft 30 of the upper roll is connected The rolls are set so that their axes incline at an angle of from about twenty to forty degrees, more or less, to a vertical plane, the inclination of the twin roll axes being in an opposite direction but substantially equal in amount to the inclination of the pressure roll. In operation, the work piece is disposed horizontally in the vertical plane just mentioned and,- therefore, contacts with the surface of each of the two twin rolls at positions spaced considerably apart, that is, in the neighborhood of the large ends thereof, there always being a portion of the work piece opposite the single roll that is entirely clear of the twin rolls.

When the machine is set primarily for the straightening operation, the portion of the work piece between the twin rolls is bent by the pressure roll which exerts pressure thereon at a point or line on the work piece midway between the twin rolls. As the rolls are continuously rotating and the work piece is continuously both rotating and progressing axially, all portions of the work piece undergo the same bending action which causes the fibres of the work piece to be stretched in exactly the same manner around the neutral axis of the work piece. This uniform stretching of the fibres causes the work piece to remain straight after having passed through the machine. Therefore, if the work piece is straight when it enters the machine, the action of the machine merely polishes the surface of the work piece. If the work piece is bent or kinked when it enters themachine, then the fibres opposite the bend, that is, the fibres on the concave side of the bend or kink, will be stretched to a greater extent than the fibres in the straight section of the workpiece. This additional stretching will neutralize the additional stretch in the fibres causing the bend or kink. Since the action is uniform across any diameter, the net result is a balancing of forces in the stretched fibres and the production of a straight work piece. The pressure roll is so adjusted vertically that its band or zone of least diameter bears against and flexes the work piece about midway between its points of contact on the twin rolls. When the shaft, bar or tube is in position between the twin rolls and the pressure rolls, the pressure of the pressure roll thereon bends it in reverse direction to a point beyond the limit of elasticity of the metal so that, when the pressure is released, such portion will be straight.

When the machine is to be used for polishing the work piece, the rolls are set at such angles that the work piece 'flexed by the pressure of the pressure roll is in contact with the three rolls over substantial distances, throughout which the peripheral speed of the rolls varies, due to the variation of their diameters, while the diameter of the work piece remains substantially constant. Consequently, there is a rubbing action of the rolls on the work piece which effectively polishes or burnishes thework piece. The flexing of the work piece by the pressure roll will cause it to conform to the curvature of the surfaces of the rolls presented to the work piece so that the differential in surface velocity of the curved roll surfaces has a bumishing action on the work piece. form due to the fact that'the diameter of the work piece is constant.

Work pieces of different physical character- The work piece surface velocity is uni- .istics and difierent diameters require the rolls to be set differently. Since certain of the fibres of the work piece must be stretched beyond the elastic limit ofthe material, a work piece with a low elastic limit material may be straightened with a comparatively shallow setting of the pressure roll; and the angle of the rolls with relation to the work piece may approximate the upper limit of the permissible working angle. When the material of the work piece has a much higher elastic limit, the pressure roll is set much deeper in order that the bend in the work piece be increased to a point where the fibres will be stretched beyond the elastic limit. A similar result may be obtained by changing the angularity of the rolls since a lesser angle with, the work piece will present a deeper roll surface thereby causing a deeper bend in the work piece. The lesser angle also has the added effect of increas-. ing the number of straightening cycles per foot of work piece length. This increased number of straightening cycles will assist in straightening higher tensile strength material.

The setting of the machine for work pieces of different diameters is effected by shifting the pressure roll radially by means of the vertical adjusting device hereinbefore described, the pressure roll being-shifted outwardly for a work piece of larger diameter and inwardly for a work piece of smaller diameter. Along with this radial shifting of the pressure roll, the angularity of the rolls with respect to the workpiece is changed.

In view of the fact thattlie contact of the work piece with the roll surface merely approximates a straight line contact over a very short length,

in any provision of setting of themachine it is necessary to change the angularity of the rolls when the work piece diameter changes. The larger diameter work pieces require that the rolls be set at a larger angle with the work piece. A

variation of both factors, namely, a change in,

the elastic limit of the material together with a change in the diameter of the work piece, may require very little change in the setting of the angle of thewolls. Thus, when the work piece diameter changes, the first change to be made -in the setting is to increase (or decrease) the roll opening or distance between the pressure roll and the twin rolls. The next is to change the angularity of the rolls to a greater angle or a smaller angle as required by the diameter of the work piece and the elastic limit of the material.

It is preferable to use a guide for directing the work piece through the machine, which guide may be of suitable conventional type. However, such guide may be dispensed with if the large ends of the rolls are properly designed for the purpose. In the construction illustrated, this guide comprises two plates 35 located in a plane substantially parallel with the plane of the axis of the twin rolls and on opposite sides of the work piece and suitable means 36 for adjusting said plates respectively in their planes radially with relation to the work piece. The inner edge of eachplate is straight and parallel with the axis of the work piece, but one end portion of each plate, as at 31, is cut away to clear the adjacent end of the pressure roll.

While my machine is primarily designed for use in straightening rods and tubes, more or less polishingis done as an incident to the straightening. Such polishing is eifected by the rubbing of the surfaces of the rolls over the surface of the work piece. Rubbing implies that there is a difference between the peripheral speed of the work piece and the peripheral speed of the rollers at the points of rubbing. Such difference of peripheral speed is due to the difference in diameter between the smallest diameter of the upper roll and the diameters of the twin rolls at their points of contact with the work piece and also to the fact that, due to the bending of the work piece in the normal operation of the device, there is a considerable portion of the length of each twin roll and the pressure roll in contact with the work piece hereinbefore mentioned, and the diameters of the rolls are changing throughout these portions.

It is noted as an important advantage of my invention that it will" operate successfully with work pieces of widely different diameter; and particularly that it is capable of straightening workpieces of smaller diameter than can be straightened by any other three-roll cross roll mills. This is due to the fact that the overlapped'end portions of the twin rolls are of smaller diameter than their outer ends, whereby the interference of the rolls with one another is avoided and a smaller pass can be formed.

It is also noted that the rolls of my machine may be adjusted throughout a wide angular range and may be set at as large an angle as is practicable with other straightening machines with skewed rolls. It is also noted that the unsupported length of the work piece from one twin roll to the other twin roll can be made shorter than is possible with any other cross roll straightening machine that I know of. Thus the rolls may be adjusted to meet the requirements of the work and the machine is capable of removing short kinks as well as long bends in a single passage of the work piece therethrough.

I have hereinbefore described the work rolls as having hyperboloidal surfaces, as such surfaces are particularly advantageous and efiective in the matter of polishing the work piece. Insofar as straightening alone is concerned, all three -of the rolls may be cylindrical, or the twin rolls a plane passing through it perpendicularly to the plane of the parallel axes intersects said parallel axes at an oblique angle, means operatively connected to each of-said rolls to drive it positively, and means for guiding the work piece axially between said third roll and the other two rolls.

2. A machine for straightening rods and tubes, 4

said machine comprising two tapered rolls arranged withtheir small ends overlapping and with their axes substantially parallel and a third roll located opposite said first mentioned rolls and disposed with its axis in a plane substantially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through it perpendicularly to the plane of the parallel axes intersects said parallel axes at an oblique angle, means for guiding the work piece axially between said third roll and the other two rolls, means operatively connected to each of said rolls to drive it positively and means for adjusting said third roll towards and from the plane of the other two rolls.

, means operatively conneqted to each of said rolls & aieaeca 3. A machine for straightening rods and tubes, said machine comprising two tapered longitudinally concave rolls arranged with their smaller ends overlapping and with their axes substantially parallel and a third longitudinally concave roll located opposite said first mentioned rolls and disposed with its axis in a plane substantially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through it perpendicularly to the plane of the parallel axes intersects said parallel axes at an oblique angle. and

to drive it positively.

4. A machine for straightening rods and tubes, said machine comprising two longitudinally concave rolls with hyperboloidal surfaces with their axes substantially parallel and a third longitudinally'concave roll with a. hyperboloidalsurface with its axis in a pane substantially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through it perpendicularly to the plane of the parallel axes will intersect said parallel axes at an oblique angle, the parallel rolls being of smaller diameter at one end than at the other and being disposed with their smaller end portions in overlapping relation.

A machine for straightening rods and tubes, said machine comprising twolongitudinally concave rolls with hyperboloidal working surfaces with their axes substantially parallel and a third longitudinally concave roll with a hyperboloidal working surface with its axis in a plane substanv tially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through it perpendicularly to the plane of the parallel axes will intersect said parallel axes at an oblique angle, the

working surfaces of the parallel rolls being of smaller diameter at one end than at the other and being disposed with their smaller end portions in overlapping relation and means for adjusting said third roll towards and from the plane of the other two rolls.

, 6. A machine for straightening rods and tubes, said machine comprising a member rotatably adjustable in its own plane, two rolls mounted on said member with their axes substantially parallel and on opposite sides of the axis of adjustment of said member, a yoke opposite said rolls, means for adjusting said yoke rotatably and toward and away from said first mentioned rolls, and a third roll with its axis in a plane substantially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through it perpendicularly to the plane of the parallel axes intersects said parallel axes at an oblique angle.

7. A machine for straightening rods and tubes, said machine comprising a horizontally rotatable member. two longitudinally concave rolls mounted on said member with their axes substantially horizontal and parallel, a yoke opposite said rolls, means for adjustingsaid yoke rotatably and vertically, and a third horizontal longitudinally concave roll with its axis in a plane substantially h parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a. plane passing through it perpendicularly to thevplane of the parallel axes intersects said parallel axes at an oblique angle, said member and said yoke being rotatably adjustable about the same axis.

8. A machine for straightening rods and tubes, said machine comprising a member, two longitudi ally concave hyperboloidal rolls mounted on said member with their axes substantially parallel, a yoke opposite said rolls, means for adjusting said yoke rotatably and vertically, and a third hyperboloidal longitudinally concave roll with its axes in a plane substantially parallel with but spaced from the plane of the axes of said first mentioned rolls and so positioned that a plane passing through 'it perpendicularly to the plane of the parallel axes intersects said parallel axes at an oblique angle, the working surfaces of said parallel rolls being of smaller diameter at one end than at the other and being disposed with their smaller end portions in overlapping rela-' tion, said member and saidyoke being rotatably adjustable around the same axis perpendicular to the planes of the axes of the rolls.

CARL DIDDEN. 

